Can I Order More Copies Of A Past Order?

Yes, you can order more copies of an order you have previously placed.

On the MILK website:

To order more copies of your project on the MILK website, you will need to navigate to your My Books page. From there, click on the Print button of the project that you have previously printed and follow the prompts to add your project to your basket and checkout.

Via the MILK Books Photos App Extension for Mac:

To order more copies of your project via the Photos App Extension, you will need to open the project you previously printed. From there, click on the Buy button to proceed through the checkout and place your order.